The present invention is directed to biologic methods, processes, microorganisms, and apparatus for producing products, materials, intermediates, and the like such as organic acids, single cell protein (xe2x80x9cSCPxe2x80x9d), hydrogen, alcohols, and organic acid salts from the waste gas streams of certain industrial processes and more particularly concerns a process utilizing continuous gaseous substrate fermentation under anaerobic conditions to accomplish this conversion.
The conventional procedure for producing organic acids, alcohols, hydrogen and organic acid salts is chemical synthesis of petroleum-derived feedstocks. The rapidly escalating cost of petroleum has generated considerable interest in producing these valuable commodities by fermentative processes that utilize renewable or waste materials as the feedstock. Single cell protein is produced as a by-product of the fermentations, and is generally used as an animal feed supplement.
There is also growing concern over the massive amounts of atmospheric pollutants and greenhouse gases produced by conventional industrial processes. The Environmental Protection Agency recently estimated that over six million metric tons of carbon monoxide and nearly four million metric tons of hydrogen were discharged annually by the industrial complex. A substantial portion of this waste carbon monoxide and hydrogen is the result of carbon black manufacture and coke production, roughly 2.6 million metric tons of carbon monoxide and 0.5 million metric tons of hydrogen. Large amounts of carbon monoxide or hydrogen are also produced by the ammonia industry (125,144 metric tons of carbon monoxide in 1991), petroleum refining (8 metric tons per thousand barrels), steel mills (152 pounds per metric ton of steel produced), and sulfate pulping of wood (286 pounds per ton of pulp). In 1991, the adipic acid industry generated 40,773 metric tons of carbon monoxide that was burned for fuel value or flared. In many cases, these gases are discharged directly to the atmosphere, placing a heavy pollution burden on the environment.
Typically, the waste gases from the manufacture of industrial products are released at low pressures and temperatures. Current technology cannot utilize these dilute gases under such conditions. Adapting existing technology to separate and recover hydrogen or carbon monoxide from these waste streams would be expensive and impractical.
In light of the foregoing, there exist needs in the art for cost effective and practical methods, microorganisms, and apparatus for utilizing the above-described waste gases and for producing products, materials, intermediates and the like such as organic acids, alcohols, hydrogen and organic acid salts by other than chemical synthesis of petroleum derived feedstocks.
In accordance with the present invention, products, materials, intermediates, and the like such as organic acids, alcohols, hydrogen, single cell protein and/or organic acid salts are produced from the waste carbon monoxide, hydrogen, and/or carbon dioxide of industrial processes, thereby reducing environmental pollution while at the same time saving energy and chemical feedstocks.
In accordance with an exemplary process of the present invention, the desired components of the dilute gas mixtures are introduced into a bioreactor containing one or more cultured strains of anaerobic bacteria that utilize the waste gas components by a direct pathway to produce a desired compound. The compound is recovered from the aqueous phase in a separate vessel or vessels, utilizing a suitable recovery process for the compound produced. Examples of recovery processes include extraction, distillation or combinations thereof, or other efficient recovery processes. The bacteria are removed from the aqueous phase and recycled to avoid toxicity and maintain high cell concentrations, thus maximizing reaction rates. Cell separation, if desired, is accomplished by centrifugation, membranous ultrafiltration, or other techniques.
The principal object of the present invention is the provision of a process and/or microorganism for the production of products, intermediates, materials, and the like such as organic acids, hydrogen, single cell protein, alcohols, and/or organic acid salts from carbon monoxide, hydrogen, and/or carbon dioxide.
Another object of the present invention is the provision of methods, microorganisms and apparatus for the production of items such as organic acids, alcohols, hydrogen, single cell protein and/or salts from the waste gas streams of industrial processes such as oil refining, and production methods for generating carbon black, coke, ammonia, and methanol.
A still further object of the present invention is the provision of a process for producing acetic acid and/or ethanol from a waste gas stream of identical composition to that found in the manufacture of carbon black.
Yet another and more particular object of the present invention is the provision of a method, microorganism and apparatus involving continuous gaseous substrate fermentation under anaerobic conditions to accomplish the conversion of waste gas streams of certain industrial processes into useful products such as organic acids including acetic acid, alcohols, hydrogen, single cell protein and organic acid salts.
Other objects and further scope of the applicability of the present invention will become apparent from the detailed description to follow, taken in conjunction with the accompanying drawings wherein like parts are designated by like reference numerals.